Chemical Characterization of the Oil Separated by Mechanical Pressing from Strychnos madagascariensis Dried Fruit Pulp Flour.

Sandra S I Chemane,Olívia Pinho,Susana Casal,Maida Khan,Rebeca Cruz,Olga Viegas,Teresa Pinho

doi:10.3390/foods11030474

Abstract

In Mozambique, rural communities produce flours from the dried pulp of Strychnos madagascariensis fruits. Owing to its high lipid content, the oil from this flour is frequently separated by pressing to be used as seasoning and medicine. Aiming to characterize this oil, flour samples (n = 24), dried at two different temperatures (55 °C and 65 °C), were collected from four local communities, together with a control sample prepared in the lab (50 °C). The resulting oil was fluid at room temperature, deep orange, and characterized by a high content of oleic acid (62–63%), followed by palmitic (20%) and linoleic (7%). It contained considerable amounts of tocols (25–34 mg/100 g) and carotenoids (8–10 mg/100 g), as well as sterols (431 ± 10 mg/100 g) and triterpenic alcohols (823 ± 4 mg/100 g mg/100 g). The overall composition was highly consistent between origins and temperatures, with only small statistically significant differences (p < 0.05), mostly between the community dried flours and control group. However, its high free fatty acid content (22–25%) reveals intensive enzymatic hydrolysis during the drying/fermentation steps, whose extension can be reduced by optimizing its technological process. Its chemical profile supports some of its folklore uses, revealing that it can be a promising source of edible oil, with health and technological potential that is worth optimizing and exploring.

Highlights

The Strychnos genus belongs to the Loganiaceae family, indigenous to tropical and subtropical Africa
S. madagascariensis fruits, known as monkey orange, are usually eaten raw, or fermented and dried by sun exposure and used to make alcoholic beverages, and the pulp produces an appreciated sweet when mixed with honey or in the form of tea [1,2,3]
The oils obtained from the S. madagascariensis fruit flours prepared from the four communities (Marracuene, Manhiça, Chókwé and Chicualacuala) were characterized for fatty acids composition, glycerides, phytosterols, tocols and carotenes

Summary

Introduction

The Strychnos genus belongs to the Loganiaceae family, indigenous to tropical and subtropical Africa. S. madagascariensis fruits, known as monkey orange, are usually eaten raw, or fermented and dried by sun exposure and used to make alcoholic beverages, and the pulp produces an appreciated sweet when mixed with honey or in the form of tea [1,2,3]. Due to their abundance, the preservation of Strychnos sp. In the southern part of Mozambique, where the fruit is called “macuácua” (“Makwakwa”), it is usually eaten after being transformed into a flour-like product obtained from the dried pulp (“nfuma”), especially in times of scarcity of basic foods. Some communities extract a liquid oil with intense orange-brown color from “nfuma” with several applications, including cooking purposes

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